I'm middle class and lived in Paris. I had rich friends and poor friends. My rich friends owned flats that occupied entire floors of a building. My poor friends got whatever social housing was available. And my middle class friends rented or bought a place in the suburbs with more space. We owned, a relatively small by American standards 55sqm, 3F, flat in the city center. My middle class friends could also rent the same size flat on their salaries but none of them wanted to. They liked their space and garden.

Their is give and take to everything in life. I don't think it's hard to live in Paris if you're in the middle class, but you certainly won't feel middle class doing it.